The present invention relates to automated glassware forming apparatus, and more particularly to improved electronic control systems for such glassware forming apparatus.
A widely accepted type of apparatus for forming glassware articles, known as the Hartford I.S. (or "individual section") machine, is exemplified by U.S. Pat. No. 1,979,211. These machines incorporate a master timing cam mounted to a machine drive shaft to actuate various "forming events" during each glassware forming cycle, by controlling various valves to pneumatically operate various mechanisms within each machine section. The specific motion of given mechanisms may be further controlled by cams, pneumatic control mechanisms, and the like. Typically a given I.S. machine includes a plurality of sections (e.g. eight) which are coordinated in the infeed of molten glass from a common gob distributor, and in the removal of formed glassware articles for further processing.
With the advent of electronic process control technology, various improvements to the above machine design have been made in controlling the timing of various forming operations. An initial stage of this adaptation was the replacement of the mechanical timing control of the master cam with digital electronic apparatus which generated actuation pulses for, e.g., solenoid-actuated valve blocks. See, e.g., U.K. Patent No. 1,079,385. This electronic timing control was tailored to the special processing requirements of the glassware forming process in U.S. Pat. Nos. 3,877,915 and Re. 29,188, which characterized the machine timing by critical thermodynamic milestones of the forming process--i.e. "thermodynamic boundary events". These and other inventions provided increasingly sophisticated machine-level timing control over forming events, machine start and stop functions, and the like.
More recently, such electronic control systems have added an additional heirarchy of section-level controllers; see, for example U.S. Pat. Nos. 4,152,134; 4,247,317; and 4,478,629; and EPC application No. 84300470.6. Different systems employing such section-level controllers vary in such characteristics as whether the section controllers are capable of independent operation (as opposed to requiring downloading from a supervisory machine controller), and the nature of operator interaction. All of these approaches offer only a limited, on-off control over the operation of given forming mechanisms.
It is also known to provide some degree of feedback control over the mechanisms of an I.S. machine and related machine elements. For example, the system of U.S. Pat. No. 4,108,623 employs feedback sensors in a centrally-oriented control system, which can vary the duration of various timing events in response to the sensor output. Such systems, again, provide only a limited degree of control over given forming mechanisms.
Another recent development in the interest of improved speed, efficiency, and reliability of such glassware forming machines relates to the drive mechanisms for I.S. machine components and related input and output equipment. In lieu of the pneumatic and cam driven mechanisms of traditional glassware forming machines, various servo actuator systems have been incorporated for such mechanisms as the gob distributor, bottle pushout etc. See, e.g., U.S. Pat. Nos. 4,367,087; 3,871,858; 4,456,462; 4,461,637; 4,427,431; and 4,409,013. These devices have not, however, been effectively integrated in a comprehensive electronic control system, but have entailed stand-alone controllers with quite limited interactions with the machine and section controllers.
European Patent Application No. 84105048.7, filed May 6, 1983, discloses a glassware forming machine electronic control system wherein machine components are mechanically linked to digitally responsive motor modules. The digitally responsive motor modules are under control of a component controller which is actuated by a conventional electronic timing control system of the type discussed above. This system is designed for an all-electric glassware forming machine, and does not accommodate a partially pneumatic, partially servomotor drive, machine design. In addition, this system provides only a limited degree of distributed control over various machine functions.
Accordingly, it is a principal object of this invention to achieve improved automation of glassware forming apparatus. A related object is to achieve a higher degree of control over given mechanisms within such apparatus. A further related object is to effectively integrate servo-controlled forming mechanisms within glassware forming machines. Such control system should enjoy a flexible design, permitting selective use of servomotor control, solenoid valve control, and a variety of other electromechanical interfaces.
Another object is to improve user-interaction in an electronic control system. A related object is to improve the physical design of electronically controlled glassware forming machines, thereby to improve the operating environment.
A further object is to improve the efficiency of glassware forming apparatus. As one aspect of this, it is important to reduce "down-time" in the inevitable event of wearing-out of parts, malfunction of mechanisms, etc. Futhermore, it is desirable that a malfunction of given forming mechanism not disable the operation of an entire I.S. machine and be easily diagnosed and serviced.